Arrangement for selectively irradiating webs

ABSTRACT

An arrangement for selectively irradiating a web includes a perforate band of a radiation impermeable substance which is guided in an endless path via a pair of guide rollers and has two juxtaposed runs in this path. A take-up roller conveys a web of material past one of the runs at a side thereof remote from the other run, the direction of movement of the web being other than parallel to that of the band and, preferably, normal thereto. An electron accelerator is provided at the far side of the run remote from the web and is effective for directing a radiation beam at the web through the perforations.

United States Patent Ihme Oct. 7, 1975 ARRANGEMENT FOR SELECTIVELYIRRADIATING WEBS Bernd lhme, Dresden, Germany Veb TextilkombinatCottbus, Cottbus, Germany Filed: Feb. 12, 1974 Appl. No.1 441,877

Inventor:

Assignee:

US. Cl 250/492 A; 250/400 Int. Cl. 1101.] 3/14 Field of Search 250/400,492 R, 492 A, 250/493, 397, 398, 399

References Cited UNITED STATES PATENTS 04 10/1959 Trump 250/492 R 452/1971 Petersen 2/197] Martin et al. 250/400 3,736,425 5/1973 Chemow250/492 A Primary Examiner-James W. Lawrence Assistant ExaminerD. C.Nelms Attorney, Agent, or Firm-Michael S. Striker [57] ABSTRACT Anarrangement for selectively irradiating a web includes a perforate bandof a radiation impermeable substance which is guided in an endless pathvia a pair of guide rollers and has two juxtaposed runs in this path. Atake-up roller conveys a web of material past one of the runs at a sidethereof remote from the other run, the direction of movement of the webbeing other than parallel to that of the band and, preferably, normalthereto. An electron accelerator is provided at the far side of the runremote from the web and is effective for directing a radiation beam atthe web through the perforations.

9 Claims, 6 Drawing Figures US. Patent OCt. 7,1975 Sheet 2 of2 3,911,281

ARRANGEMENT FOR SELECTIVELY IRRADIATING WEBS BACKGROUND OF THE INVENTIONThe invention relates generally to an arrangement for selectivelyirradiating webs, particularly textile webs. More specifically, theinvention relates to an arrangement for selectively irradiating webswhich is of the type wherein a template is interposed between the weband the radiation source, which latter may be an electron accelerator.

The selective irradiation of a web of material may sometimes bedesirable such as, for instance, when it is desired to texturize orstructurize the'material. The complete process whereby the structurizingeffects are achieved is not of importance here, the important pointbeing that there are cases where it is necessary or desirable toselectively or locally irradiate a web.

An arrangement is known with which localized or selective irradiationmay be performed continuously.

Here, four guide rollers are utilized, these being mounted for rotationabout axes extending normal to one another. A band is engaged by therollers is conveyed thereby in an endless path, the band being providedwith perforations which are arranged in a pattern corresponding to thepattern of selected irradiation which it is desired to achieve. The bandpasses beneath the scanner of an electron accelerator and a web to beirradiated is conveyed below the band so that the latter is interposedbetween the accelerator and the web. The band and web are conveyed insuch a manner that their relative speed beneath the scanner of theelectron accelerator is zero.

This prior art arrangement possesses certain disadvantages. Thus, thewidth of the perforated band must be equal to at least the width of theweb to be irradiated. Furthermore, since four rollers are used forconveying the perforated band, the direction of movement of the latterchanges four times along one complete circuit of the endless path. Thelarge number of changes in the direction of movement of the perforatedband makes it difficult to convey the same and, in addition, causes theperforated band to be highly stressed. This, in turn, results in highproduction costs as well as a reduction in the life of the perforatedband.

SUMMARY OF THE INVENTION It is, accordingly, a general object of theinvention to provide a novel arrangement for selectively irradiatingwebs of material. a

More particularly, it is an object of the invention to provide anarrangement for selectively irradiating webs of material whereby theirradiation and, hence, the structurizing, of the webs may be performedmore economically than was possible heretofore.

Another object of the invention is to provide an arrangement forselectively irradiating webs of material wherein the width of theperforated band is independent of the width of the web to be irradiated.

A further object of the invention is to provide an arrangement forselectively irradiating webs of material wherein the perforated band isless highly stressed and has a longer life than in the prior artarrangements.

In pursuance of the above objects and of others which will becomeapparent, the invention provides an arrangement for selectivelyirradiating a web of material, particularly textiles and the like, whichcomprises a band of a substantially radiation impermeable substance. Theband has perforations and moving means is provided for moving the bandin an endless path wherein the band has two juxtaposed runs. Conveyingmeans serves for conveying a web of material in another path which has aportion overlying one of the runs at a side of the latter remote fromthe other of the runs. The direction of movement of the web in theaforementioned portion of the path in which the web is conveyed defineswith the direction of movement of the band in either of the runs thereofan angle greater than 0 and less than 180. lrradiating means is providedat the far'side of the run remote from the one which the web overlies,that is, at the side of this run which is furthest removed from the web,and is effective for directing a radiation beam through the perforationsat the earlier mentioned portion of the path in which the web isconveyed.

The perforations in the band may be in the form of elongated slits thedirections of elongation of which define an oblique angle with thedirection of movement of the band in either of its runs. Preferably,this oblique angle equals about 45.

The irradiating means may be an electron accelerator although otherradiation sources may also besuitable for use in an arrangementaccording to the invention. The moving means should move the band insuch a manner that the direction of movement of the band in either ofthe runs thereof is opposite to that in the respective other run.Advantageously, the angledefined between the direction of movement ofthe web in at least that portion of its path which overlies a run of theband and the direction of movement of the latter in either of the runsis substantially that is, the directions of movement of the web and bandare advantageously normal to each other. 7

The moving means may comprise a pair of spaced guide rollers engagingtheband and, hence, thedirection of movement of the band along acomplete circuit of its endless path need change only twice. Byutilizing an arrangement in accordance with the invention, the length ofthe band need be only slightly greater than twice the width of the web,whereas the width of the band may correspond approximately to theeffective width of the radiation beam and may be very small without,however, impairing or interrupting the periodicity or repetitiveness ofthe perforation pattern therein. a

It will be appreciated that, where the band is conveyed in its endlesspath via a pair of spaced guide rollers about each of which'itsdirection of movement changes, and where the perforations in tthe bandare in the form of elongated slits, that the perforations in one of theruns will intersect or cross the perforations in the other run as theband moves. In order to optimize the selective or localized irradiation,it is favorable when the speeds of the web and the band are chosen so asto be substantially equal. In the event that the parameters such as theangle of inclination of the elongated slits to' the direction ofmovement of the band and the speeds of the web and the band deviate fromthe values and relationships given above, then, in order to optimize theselective irradiation, the velocity vector at the intersection of twoslits in the respective runs should be selected so as to correspond indirection and magnitude to the velocity vector of the web.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side view schematicallyillustrating an arrangement according to the invention;

FIG. 2 is a plan view of the arrangement of FIG. 1; and

FIGS. 36 illustrate different irradiation patterns which may be obtainedwith an arrangement according to the invention together with theconfigurations and distributions of the perforations used to obtain therespective patterns.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIGS. 1 and 2of the drawing, an arrangement in accordance with the invention is seento include a band or belt 1 which, for optimum results, should be of asubstantially radiation impermeable substance. A pair of spaced guiderollers 3 engages and moves the band 1 in an endless path and thedirection .of movement of the band 1 is indicated by the arrow A.

The band 1 defines two juxtaposed runs 9 and 10 in its path of traveland a pair of depressing rollers 4 depresses the band 1 so that the runs9 and 10 are in close proximity to one another. Although the runs 9 and10 are here shown as having a substantially horizontal orientation, thisneed not be so. It will be appreciated that the guide rollers 3constitute moving means for moving or conveying the band 1 in an endlesspath.

As best seen from FIG. 2, the band 1 is provided with perforations 7 andthe latter are here illustrated as being in the form of elongated slits.The direction of elongation of the slits 7 and the direction of movementA of the band 1 define with each other an oblique angle which ispreferably 45 as shown.

A web 5 of material, for example, a textile, is continuously conveyed inthe direction indicted by the arrow B and a portion of the path alongwhich the web 5 moves lies beneath the lower run 10 of the band 1.Advantageously, the direction of movement B of the web 5 is normal tothe direction of movement A of the band 1 as shown although it issufficient if the directions A and B define with each other an obliqueangle greater than and less than 180. The conveying means for conveyingthe web in the direction B may, for instance, include a feed roller 11and a take-up roller 12, although other suitable conveying means may beused. A suitable drive 6 may be provided for synchronizing the speedswith which the band 1 and the web 5 move along their respective paths.

An irradiating device, here illustrated as being an electron accelerator13 provided with a scanner 2, is located above the upper run 9. Ofcourse, other irradiating means may also be used. The accelerator 13 iseffective for directing a radiation beam, in this case, an electronbeam, at or towards that portion of the path of the web 5 below thelower run of the band 1.

The operation of the novel arrangement may be best understood from FIG.2. In the position illustrated in this FIGURE the slit 7a in the upperrun 9 and the slit 7b in the lower run 10 intersect or cross one anotherat three locations such as, for example, at the location C. It is onlyat such intersections that the radiation beam is able to effectivelypenetrate the band 1 and reach the web 5 since it is only at suchintersections that an opening is defined which extends from that side ofthe upper run 9 at which the accelerator 13 is located to that side ofthe lower run 10 at which the web 5 passes thereby. As the band 1 nowcontinues to move in the direction of the arrow A, the slit 7a will movetowards the right whereas the slit 7b will move towards the left. Theeffect of this will be that the intersection C of the slits 7a and 7bwill move towards this location C, that is, the intersection C will movein the direction of movement B of the web 5. By properly synchronizingthe speeds of movement of the web 5 and the band 1, the region of theweb 5 which was exposed to the radiation beam at the location C will bethe same region thereof which is exposed to the radiation beam at thelocation C. In other words, by proper synchronization of the speeds ofthe web 5 and the band 1, the region of the web 5 to be irradiated willmove in the direction B at the same speed as the intersection C of theslits 7a and 7b moves in this direction. Of course, the speeds of theweb 5 and the band 1 should be so selected that the region of the web 5to be irradiated will receive a sufficient radiation dose, that is, thespeeds should be so selected that the dwell time in the radiation fieldof each region of the web 5 to be irradiated is long enough for it toabsorb the desired radiation dose. The radiation pattern obtained byusing the perforation pattern shown in FIG. 2 is illustrated in FIG. 3.

By varying the distance between the perforations, the number ofperforations, the shapes of the perforations and the positions of theperforations, different radiation patterns may be obtained. FIGS. 46illustrate a few of the diverse radiation patterns which may be obtainedin accordance with the invention and, in each case, the shape anddistribution of the perforations used to obtain the correspondingradiation pattern is also shown. 7

It will be apparent that the novel arrangement is very versatile andthat any desired radiation pattern may be obtained by interchanging therelatively small band 1. It is, therefore, understood that theembodiment described above in detail is only exemplary of the inventionand is not intended to limit the latter in any manner.

One of the many applications for which the invention may be used residesin the structuring of materials. In the following Example, which is tobe considered as exemplary only and not as limiting the invention in anyway, a process for structuring materials will be described:

EXAMPLE An arrangement for conveying a band in an endless path,corresponding to that shown in FIGS. 1 and 2,

and having a length of 2.75 meters and a width of 0.5

meters, is provided beneath the scanner .of an electron accelerator. Thescanner has a width of 2.5 meters and the electron accelerator has apower output of 1 MeV and generates an electron beam having a radiationintensity of 4.10 rad/sec. A band having a perforation patterncorresponding to that of FIG. 3 is provided and has a length of 6 metersand an effective width of 0.30

meters. An unpatterned polyamide mesh is conveyed beneath the band inthe manner of FIGS. 1 and 2. The polyamide mesh has a width of 2 metersand a mass per unit area of 150 g/m. The polyamide mesh is conveyedbeneath the band at a speed of m/min and the speed of the band in itsendless path is also 10 m/min. The selectively or locally irradiatedregions of the polyamide mesh such as the regions shown in FIG. 3 absorba radiation dose of 7.210 rad. Subsequent to the irradiation, thepolyamide mesh is treated with acrylic acid and graft polymerization ofthe latter and the polyamide mesh occurs. As a result, the graftpolymerized locally irradiated regions of the polyamide mesh shrink and,consequently, structuring of the polyamide mesh is obtained and apatterning effect is visible.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofconstruction and uses differing from the types described above.

While the invention has been illustrated and described as embodied in anarrangement for selectively irradiating webs, it is not intended to belimited to the details shown, since various modifications and structuralchanges may be made without departing in any way from the spirit of thepresent invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims:

1. An arrangement for selectively irradiating webs of material,particularly textiles and the like, comprising a band which issubstantially impermeable to radiation having an energy less than apredetermined value, said band being provided with perforations so as topermit the passage therethrough of radiation having an energy less thansaid predetermined value; moving means for moving said band in anendless path wherein said band has two juxtaposed runs; conveying meansfor conveying a web of material in another path having a portion which.extends across one of said runs at a side of the latter which faces awayfrom the other of said runs, said conveying means being arranged so thatthe direction of movement of said web in said portion defines with thedirection of movement of said band in either of said runs an anglegreater than 0 and less than 180; and irradiating means at a side ofsaid other run which faces away from said one run and being adapted todirect a beam of radiation having an energy less than said predeterminedvalue through said perforations at said portion.

2. An arrangement as defined in claim 1, wherein said perforationscomprise elongated slits the directions of elongation of which definewith the direction of movement of said band in either of said runs anoblique angle.

3. An arrangement as defined in claim 2, wherein said oblique angle issubstantially 45.

4. An arrangement as defined in claim 1, wherein said angle issubstantially 5. An arrangement as defined in claim 1, wherein saidangle is an oblique angle.

6. An arrangement as defined in claim 1, wherein said runs have asubstantially horizontal orientation.

7. An arrangement as defined in claim 1, wherein said moving meanscomprises a pair of spaced rollers engaging said band.

8. An arrangement as defined in claim 1; and further comprisingsynchronizing means for synchronizing the speeds of said band and saidweb.

9. An arrangement as defined in claim 1, wherein said irradiating meanscomprises an electron acceleratOI'.

1. An arrangement for selectively irradiating webs of material,particularly textiles and the like, comprising a band which issubstantially impermeable to radiation having an energy less than apredetermined value, said band being provided with perforations so as topermit the passage therethrough of radiation having an energy less thansaid predetermined value; moving means for moving said band in anendless path wherein said band has two juxtaposed runs; conveying meansfor conveying a web of material in another path having a portion whichextends across one of said runs at a side of the latter which faces awayfrom the other of said runs, said conveying means being arranged so thatthe direction of movement of said web in said portion defines with thedirection of movement of said band in either of said runs an anglegreater than 0* and less than 180*; and irradiating means at a side ofsaid other run which faces away from said one run and being adapted todirect a beam of radiation having an energy less than said predeterminedvalue through said perforations at said portion.
 2. An arrangement asdefined in claim 1, wherein said perforations comprise elongated slitsthe directions of elongation of which define with the direction ofmovement of said band in either of said runs an oblique angle.
 3. Anarrangement as defined in claim 2, wherein said oblique angle issubstantially 45*.
 4. An arrangement as defined in claim 1, wherein saidangle is substantially 90*.
 5. An arrangement as defined in claim 1,wherein said angle is an oblique angle.
 6. An arrangement as defined inclaim 1, wherein said runs have a substantially horizontal orientation.7. An arrangement as defined in claim 1, wherein said moving meanscomprises a pair of spaced rollers engaging said band.
 8. An arrangementas defined in claim 1; and further comprising synchronizing means forsynchronizing the speeds of said band and said web.
 9. An arrangement asdefined in claim 1, wherein said irradiating means comprises an electronaccelerator.